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Old May 30th 09, 04:03 PM posted to rec.radio.amateur.antenna
Richard Clark Richard Clark is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 2,951
Default Loop antenna matching question

On Sat, 30 May 2009 07:19:26 GMT, Owen Duffy wrote:

The main loop isn't anything like 2 ohms at resonance, it is much much
higher, and the voltage is quite high for a given power.


Hi Owen,

By your latest comment, it appears you have jumped off the rails
completely. Let's look at the spec:

On Wed, 27 May 2009 13:36:53 -0400, Michael Coslo
wrote:
It's Octagonal, .75 inch copper tubing, around 8 feet in diameter. It's
designed to just reach into the 80 meter voice segment with it's
capacitor setup.

which through any of several methods reveals radiation resistance
equals 0.27 Ohms. The need for large conductors, high voltage
components, and loop (which, for 80M would be half a meter) coupling
to obtain the proper match are all found in their proper
relationships.

Upper end is either 17 or 15 meters.

where the ratio of the physical dimensions to the wavelength (roughly
half wave) renders a much higher value.

Reggie covered all of this years ago. Unfortunately, he buried the
best of his legacy in a drift of bantering making it an extreme chore
to mine Google for the relevant postings.

73's
Richard Clark, KB7QHC